1. Field of the Invention
The present invention relates to a pocket knife with a lock design, in particular to a foldable knife that provides supplemental driving force to extend the blade of the knife from the handle to an open position by a semi-automatic operation.
2. Description of Related Arts
The current designs of pocket knives can be categorized as the flick knife and the foldable knife. The flick knife utilizes the pressing force on the lock release mechanism of the handle to unlock the spring, and then the recoiling force of the spring causes the blade to shoot out from the front end of the handle. According to the designs of flick knives, the blade moved by the recoiling force of the spring can also cause bodily harm to the user if the flick knife is not properly handled. If the flick knife is dropped accidentally when being carried or operated improperly, the razor-sharp blade may be ejected automatically when the knife falls to the ground and receives a jolt.
However, by the design of the foldable knife, the movement of the blade is controlled by a pivot joint, and the blade has to be opened out and returned manually, and is received in the inner space of the handle. Unlike the flick knife, the foldable knife does not use any spring mechanism to extend the blade from the handle. This design makes it safer to operate but, at the same time, sacrifices some operability.
Since the design of conventional foldable knife cannot provide automatic opening of the knife and operation safety at the same time, a modified foldable knife has been proposed by the applicant, in which the structure of the modified foldable knife has incorporated a supplemental driving aid, formed by a holding block, a guide roller and a resilient pin installed inside the handle, such that when the user pulls out the blade from the handle of the knife at a predetermined angle, then a supplemental driving force will be produced by the action of the resilient pin to assist the extension of the blade to the open position, thus enhancing the operability by means of a semi-automatic operation.
Although the modified foldable knife design is able to meet the users"" expectation for automatic operation, the mechanical driving aid of the foldable knife requires the addition of a guide roller in the handle corresponding to the side wall of the blade that takes the pressure from by the resilient pin. therefore, the thickness of the handle has to be increased to meet the above requirement. However, the enlarged size of the foldable knife will affect the portability of the knife, and also the guide roller and the resilient pin as part of the mechanical driving aid to supplement the extension of the blade do not work in perfect unison at all times.
The main object of the present invention is to provide a pocket knife with a lock design incorporating a supplemental mechanical driving aid to solve the prior art problem of thickness of the foldable knife and to improve the supplemental driving force when extending the blade from the handle.
To this end, the present invention uses a pivot joint at the front end of handle to control the movement of the blade, a safety lock placed inside handle corresponding to the side wall of blade in the closed position, and a resilient pin installed in the handle corresponding to the back end of the blade, wherein the back end of the blade has a shoulder for engaging the resilient pin and a pin catch. The safety lock has a spring tab with a raised head, which is used to press against the back end of the blade when the blade is being extended from the handle, and the resilient pin is installed inside the chamber of the handle, where one end is fixed, and the other end is pushed against the shoulder of the blade, for supplemental driving force blade when the blade is being extracted from the handle.
The present invention provides a pocket knife with a foldable design that allows the blade to be received within the inner space of the handle.
The present invention also provides a supplemental driving aid that can force the blade of a pocket knife to extend by means of a semi-automatic operation.
The present invention also provides a simplified structural design for a pocket knife by providing a suitable thickness of the handle to meet the portability and storage requirements.
The present invention is also characterized in that a resilient pin is used in the design to drive the blade directly when the blade is being pulled out from the handle to the open position.
The features and structure of the present invention will be more clearly understood when taken in conjunction with the accompanying drawings.